My reflection of Unit I

SELF EVALUATION OF UNIT I

The aspect of the assignments I am most proud of is..., I got them all done!!! I worked hard on each and every assignment. Actually, the three that I am most proud of are, building a model of a human cell. That was kind of fun. Finding stuff all around house to use and trying to be creative was challenging!! The next thing I am proud of is my microscope write up. I have had experience with microscopes and they are fascinating! Thirdly, ummm I really can't pinpoint another, but maybe my first compendium. I have never put one of those together before and that was also a challenge!!

I think I could have improved on my writing assignments. I am awful at writing!!!!! Hope it doesn't show to much!! Writing has always been my weakness. Unfortunately, this was a lot writing, but I made it through!!

My over all grade I think would be A for effort. Everyone probably says that, but I think I worked very hard and juggling 2 other courses at the same time was very hard to organize. I can perform better in the next unit of this course by organizing my time better. I need to focus on one task at a time instead of looking at everything that is due!!!

This whole unit was engaging because there was so much information. It was all very interesting, and I especially liked the chapter on cancer. I don't think I ever felt distanced from the course. I think overall I felt overwhelmed!

The actions I felt affirming was having to write what you know. It was challenging, but useful because it reinforced the information.

The one thing that puzzled me was creating this blog. I have never used one before. Some people have great looking blogs.

What surprised me was how online classes work. This is my first online class and I must say there is a lot of work!! In the classroom you are motivated by the instructor, but with online classes it all rides on your shoulders whether or not you are going to do the work.

Recombinat (bacterial) DNA insulinvs Pig Pancreatic insulin

UNIT I ETHICAL ESSAY

RECOMBINANT (BACTERIAL) DNA INSULIN VS PIG PANCREATIC INSULIN

For years scientists have been making insulin obtained from pig's pancreas and it has been very successful in the treatment of diabetics for years and years. But what do scientists do??? They research for new treatment of diseases. The recombinant DNA technology is a new treatment for diabetic patients. The scientists used a weakened strand of E. coli (already found in our bodies) as a a vector=a carrier or transporter, ie., a virus or plasmid that conveys a genetically engineered DNA segment into a host cell (us).

The pig insulin has worked for years, so you may ask yourself; If it isn't broke, why fix it??? Well, people are always looking for a new and improved treatment for a disease. The Recombinant DNA human insulin has been proven indistinguishable from pancreatic human insulin. One problem did occur with its creation, but don't all new treatments have side effects.

I believe that it is by personal choice that a diabetic patient use pig insulin or the new technology of recombinant DNA insulin. Some people may think in two ways. The pig insulin comes from a very dirty animal and with recombinant DNA this is coming for E. coli (which is infectious) and can be very dangerous if the not controlled, but E coli is already produced in our bodies and the new Recombinant DNA is a weakened form and just used as a host cell. A good example of the E. coli is similar to the flu vaccine, you are actually getting a shot of a weakened flu virus.

the study in the article I read was the concerns of hypoglycemia which is low blood sugar which diabetic suffer from. In a British study published in "Lancet" hypoglycemia was induced on patients with the pig and human insulin and the study showed "no significant differences in the frequency of signs of hyoglycaemia between the users. A British women who had been dependant on the pig insulin switched to the Recombinant DNA insulin and experienced recurring hypoglycemia. She eventually went back on the pig insulin.

Dr Simone Wolff of the University of College of London said as far as he is concerned there no fault with the human insulin . Also, he thinks they need to have a study to examine the possible risks.

Again, I believe it is personal choice and trial and error. Diabetics have it hard enough! But trying something new, never hurt anyone. I believe there will a lot more studies done with insulin and the Recombinant DNA insulin with many improvements. Scientists are geared towards finding a new treatments for diabetes. All new drugs are trial and error!

COMPENDIUM II

COMPENDIUM II

TABLE OF CONTENTS:

I. Chromosome Inheritance

A. Mitosis and Meiosis

B. Chromosomes/Karotype

C. Diseases with Chromosomes

II. CANCER

A. Cancer cells

B. Causes & Prevention

C. How Cancer is diagnosed

D. Treatments available

III. GENETIC INHERITANCE

A. One & two trait inheritance

B. Genotype & phenotype

C. Gametes

D. Genetic Disorders

E. Polygenic Inheritance

F. Sex-linked inheritance

G. X-linked disorders

IV. DNA BIOLOGY & TECHNOLOGY

A. Structure and Function of DNA RNA and Protein

B. Translation and Transcription

C. Regulation of gene expression

D. Gene Isolation & cloning

E. Genome Project

CHROMOSOMAL INHERITANCE

Chromosomes are what we inherit from generation to generation, because of the genes expressed in each chromosome. Humans have 46 chromosomes that occur in 23 pairs. 22 of these pairs are called autosomes. All of these genes control traits, except gender. The gender are determined by the one pair of chromosomes called the sex chromosomes. Males have the XY chromosome and the female has the XX chromosome. Also, an important note is the Y chromosome also contain the SRY gene that causes the male testes to develop. Chromosomes are found in out DNA. They are packaged into chromatins and when the cell divide they unravel and become chromosomes.

A Karotype is basically a picture of numbered chromosomes.

http://www.nature.com/cr/journal/v15/n5/fig_tab/7290307f2.html

Mitosis is the process of cell division during which the cell nucleus divides.

nte-serveur.univ-lyon1.fr/.../mitosis1.gif

As you can see mitosis goes through stages. Prophase is the first stage in which the chromosomes become visible. The centerioles, located in the cytoplasm near the nuclear envelop separate and take up positions on opposite sides of the nucleus. The centerioles lie in the centrosome that help to organize the spindle, a microtubule structure that helps separate the chromosomes. Then the condensed chromosomes become attached to fibers in the spindle at a point near the centromere of each chromatid. Next is metaphase. In metaphase, the chromosomes line up across the center of the cell, microtubules connect the centromere of each chromosome to the poles of the spindle. Third is Anaphase. During ananphase the centromeres that join the sister chromatids separate letting the sister chromosomes continue to move until the have seperated into two groups near the poles of the spindle. It ends when the chromosomes stop moving. The last phase is telophase. In telophase, the chromosomes which were condensed begin to disperse into a tangle of dense material. A nuclear envelop reforms around each chromosome, the spindle begins to break apart and a nucleolus becomes visible in each daughter nucleus.

Meiosis also has stages. Meiosis is the process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell.

kenpitts.net/hbio/8cell_repro/meiosis_pics.htm

Before meiosis 1 occurs each chromosome is replicated. The cell begin to divide and kind of looks like mitosis, but each chromosome pairs with its homologous chromosome to form a structure called a tetrad. There are 4 chromatids in a tetrad. This is where they may exchange portions of their chromatids in a process called crossing over. Next is metaphase and this is when the spindle fibers attach to the chromosomes. Anaphase is when the fibers pull the homologous chromosomes toward opposite ends of the cell. After the chromosomes separate two new cells are formed. Each cell contains four chromatids. But neither one of the daughter cells has two complete sets of chromosomes.

Second stage is meiosos II.

With meiosis II the two cells produced in meiosis one enter a second meiotic division. This has the four stages just like mitosis. Prophase cells have one chromosome from each homologous pair. In metaphase, two chromosomes line up in the center of each cell. In Anaphase the paired chromatids separate. Each of the four daughter cells produced is receives 2 chromatids. Four daughter cells now contain the haploid number.

Diseases can result from having to many or too few chromosomes. This can occur during the two cell divisions with I explained above. One example is non disjunction that happens during meiosis when both of a homologous pair go into the same daughter cell. Normal development relies on two of each kind of chromosomes. One disease is Down Syndrome. This is when there is an extra chromosome on chromosome 21. They say you have a better survival rate with an extra chromosome then you do with a deficiency. Another disease is Turner syndrome. This is when a child is born with only one sex chromosome. They will need hormonal supplements because they do not go through puberty or menstruate.

CANCER This is a picture of a brain cancer cell

www.alternative-cancer.net/Cell_photos.htm

Cancer cells are invasive. They have no function and look abnormal. They have a abnormal nuclei. They are large and may contain chromosomes. In a normal human cell, chromosomes end with special repetitive DNA sequences called telomeres. After binding with the correct protein the cell undergoes a process called apopstosis in which the cell dies. With cancer cells, a special enzyme telmerase continues the telomere sequences so that the cancer cell can keep growing, and growing. The cells eventually make up a tumor, they pile on top of each other and grow in layers. There are 2 types of cancers. benign is is a tumor that is encapsulated and will not invade adjacent tissue. Malignant is more serious. They can invade and destroy surrounding healthy tissue. In order for cancer cells to grow they need a well developed capillary network. Angiogenesis is the formation of new blood vessels. Cancer cells can also metastasize, meaning it can spread rapidly and invade other organs. This is terminal!! Cancer is a genetic disease. When cancer develops, the cell cycle occurs repeatedly due to mutations in two types of genes:

1. Proto-oncogenes - they code for proteins that promote the cell and prevent apotosis.

2. Tumor-suppressor genes - they code for proteins that inhibit the cell cycle and promote apoptosis.

There are several types of cancer. Most can be treated, but if it metastasizes then there is usually nothing doctors can do. Tumors are related to the organ it is associated with or has invaded. One example is leukemia. This particular cancer is associated with white blood cells. Another cancer is breast cancer. Very common in women, but men can get breast cancer too. Cancer can be hereditary. Some parents can be carriers. For example, with breast cancer scientist have found genes BRCA1 and BRCA2. These are tumor-suppressor genes that follow a particular inheritance pattern. Another type of tumor suppressor is RB gene. This is retinoblastoma, when a tumor develops in the eye. Others causes of cancer are environmental carcinogens. A carcinogen is a chemical that causes cancer. One example is radiation, like, ultraviolet rays (sun), x-rays and radon gas. These interfere with a persons DNA causing mutations. Smoking is also environmental. You don't even have to be a smoker to get cancer. People need to make healthy choices, not to smoke, eat a good diet with less red meat, and exercise. Also, people need to get regular checkup because sometimes cancer can go undetected. Women need regular pap smears and mammograms. Men need to have a prostate test done and yes some need mammograms. The American Cancer Society has seven warning signs which spells out CAUTION. C= change in bowel or bladder habits. A= a sore that does not heal. U= unusual bleeding or discharge. T= thickening or lump in breast or elsewhere. I= indigestion or difficulty swallowing. O= obvious change in wart or mole. N= nagging cough or hoarseness. Another important thing people can prevent is skin cancer. People can die from it. Melanoma is very dangerous and can start with just a small mole on your back that grows to the size of a half dollar. Keep checking moles!! Other tests that can be performed are Cat scans, MRI's, Pet scans and colonoscopy. Treatments for cancers are surgery to remove a cancerous tumor, radiation and chemotherapy. The radiation treatment causes chromosomal breakage and cell cycle disruption. People in low cancer stages are usually treated with radiation. Chemotherapy is a way to catch cancer cells that have spread throughout the body. Chemotherapy is usually given intravenously. one example of a chemotherapy drug is Alkylating agents - these medications interfere with the growth of cancer cell by blocking the replication of DNA. There are also newer therapies. One is immunotherapy, which refers to our immune system. The immune system is compromised when cancer cells attack. A vaccine called Melacine, which contains broken melanoma cells from two different sources in being studied for prevention of melanoma. There will be a lot of new therapies, as scientists keep up the research. It will never end!!

GENETIC INHERITANCE

We inherit our genes obviously from our parents. There are genotypes and phenotypes. The genotypes is generally your genetic makeup, the "genes" that you inherit. For you to inherit certain genes they have to be on the same chromosome and affecting the same trait, known as an alleles. These alleles are recognized by dominant or recessive. To separate the two they are categorized into letters. The dominant get capital letters, whereas the recessive gets lower case letters. For example, unattached earlobes are dominant over attached earlobes, so the dominant "E" for unattached and "e" for attached. There are two alleles for a given trait. Also, if the alleles is dominant; ie., EE this is considered a homozygous dominant and if it is recessive; ee it is homoozygous (meaning same) recessive. If the alleles are Ee then this is considered heterozygous. This would be considered dominant because of the leading E. Phenotype is what physical characteristics you inherit from our parent. Phenotypes can also be inheriting a disorder such as color blindness. There is also one and two trait cross inheritance, which involves gamates. Gametes are the specialized sex cells, which are the sperm of a male and an egg of a female. The gametes start out with 23 pairs of chromosomes. These chromosomes separate during meiosis. One trait crossing involves parents wanting to know if their child will a certain genotype or phenotype; ie freckles. Only "one" parent has freckles. This would depend on the allele pairing and if a parent carries this particular gene. Depending how the alleles pair there are sometimes a 50% chance that the child will have freckles. This is where the Punnett square is a useful tool in determining what the chances are a child would have freckles or unattached earlobes. The square combines all possible gametes and determine the genotype and the phenotypes of all offspring. The child or children can be homologous or heterozygous. Heterozygous refers to monohybirds in regards to having one pair of alleles. There are also two trait crosses. This involves meiosis and the gamete formation when a cross involves two traits. The alleles, of course, plays a key role in this process. What chromosomes you are inheriting from your parents, is homologue of each pair is the parental (father) chromosome and the maternal (mother) chromosome. All possible combinations of alleles occur in the gametes. Genetic disorders can occur if a parent is a carrier and some parents can be unaware that they are carriers if genetic testing is not done. One genetic disorder can be autosomal dominant in someone who has alleles AA or Aa and they will have the disorder. Someone with the recessive alleles aa will have the disorder. So a child born to heterozygous parents, has a 25% chance of having a disorder. Examples of genetic disorders are Tay-Sachs disease. This disease is an autosomal recessive disorder. It is a lack of an enzyme hexosaminidase A (Hex A) and storage of its substrate glycophingolipid in lyosomes. Occurs mainly in the brain. The symptoms are not apparent at first, but the child's development slows between four and eight months. Also has neurological impairment. These children eventually become blind, has seizures and becomes paralyzed. There are Polygenetic inheritance. Polygenic traits are skin color and height. Several sets of alleles are involved. The polygenic inheritance is like phenotype that is inherited from your parents. Skin color and height are multifactual traits because they both can effected by the environment. For example with skin color; the sun can make you darker due to the pigment in the skin. With height; if you are not the nutrition needed you could stop growing properly. Next six-linked inheritance which are controlled by genes on the sex chromosomes. An allele on the X chromosome is X-linked (mom) and the Y chromosome is Y-linked. These determine if you will be male or female when you are born. Many sex-linked genes are found on the X chromosome. The Y chromosome is much smaller then the X chromosome therefore it can carry more. Colorblindness is one of traits carried. There are three genes associated with color vision which lies on the X chromosome. In males a defective version of any one of these genes produces colorblindness. The most common form of colorblindness is not seeing the red-green colors. Males have just one X-chromosome so all the X-linked alleles are expressed in males even if they are recessive. For the female to express for colorblindness there must be two copies of the allele one on each of the two X chromosomes. There are sex-linked disorders. One example is Hemophilia. There are two important gens that are carried on the X-chromosome that help control blood clotting. A recessive allele in either of the two genes may produce this disease.

DNA BIOLOGY AND TECHNOLOGY

DNA(deoxyribnucleic acid) is the genetic material housed in the nucleus of a cell. The structure is similar to a ladder when replication is taking place. Originally, it is a double helix and is composed of two strands, each strand is a polynucleotide. The nucleotide is composed of a phosphate, deoxyribose sugar, and nitrogenous base. The phosphate-sugar combination is the backbone !! The base pairing is held together be hydrogen bonding, which are weak bonds. The bases are what is important in the functioning of DNA. The bases for DNA are Adenine and Guanine, which are purine (two rings) and Tymine and cytosine (one ring). In replication(also known as semiconservative), (one function of DNA), the cell divides and each new cell get an exact copy of DNA. In replication the one strand of DNA is separated and the base pairing, because they are held together with weak hydrogen bonds are separated. Then complementary base pairing is started. A-T always and C-T. These bases are joined together by an enzyme DNA polymerase. The DNA is originally unzipped by an enzyme helicase. The replication is complete when an enzyme seals any breaks in the sugar-phosphate backbone. I believe the enzyme is called ligase. Structure and function of RNA. RRNA (ribonucleic acid) is made up of nucleotides and the sugar ribose. The nucleotides are similar to DNA's nucleotides, except Urasil takes the place of Thymine. RNA still has Adenine, Cytosine, and Guanine. RNA has a single strand. RNA is made with help of DNA and is used for protein synethesis. There are 3 forms of RNA. mRNA is messenger RNA, used to carry genetic information from the DNA to the ribosomes, where protein synethesis occurs. Next, is tRNA, transfer RNA, is produced in the nucleus also with the help of DNA and tRNA is responsible for transferring amino acids to the ribosomes. The last RNA is rRNA, ribosomal RNA, this is made up in the nucleolus of a nucleus and DNA is used to help produce it. rRNA is involved with the ribosome where protein synthesis occurs. Transcription is when RNA molecules are produced by copying part of the nucleotide sequence of DNA into a complementary sequence in RNA. During transcription RNA polymerase binds to DNA and seaprates the DNA strands. RNA polymerase then uses one strand of DNA as a template from which nucleotides are assembled into a strand of RNA. mRNA is produced when the RNA nucleotides joins with RNA polymerase. With translation, the ribosome binds to the mRNA at the start codon,AUG, that is reconized only by the iniator tRNA. Amoni acids are linked to tRNA and bind to the appropiate codon in mRNA by forming completmentary base pairing withe tRNA anticodon. The ribosome moves from codon to codon along the mRNA. Amino acids are added one by one translated into a polypeptidic sequences dictated by DNA and represnted by RNA. At the end a release factor binds to to the stop codon terminating translation and reelasing the completed polypeptide from the ribosome. Proteins are macromolucules that contain a nitrogen as well as carbon, hydrogen, and oxygen. Proteins are also polymers of amino acids. There are more the 20 different amino acids. Protein help to carry out chemical reactions, transport small molecules in and out of cell and fight diseases.

molbioandbiotech.wordpress.com/.../ This is a picture of gene expression.

About replication, I would like to break it down.................................

Replication fork: point of unwinding DNA

Primer: starts thing off or gets things going

DNA is tightly coiled and must be uncoiled to begin replication

Uncoiling done by enzymes

DNA is made in a 5'-3' direction

Replication enzyme is DNA polymerase

DNA synthesizes enzyme

Makes new strand by finding base pair

It can find, bond to, modify at the rate of 1000 nucleotides per second

DNA polmerase can only make DNA in a 5'-3' direction

To make a new base it needs something to bond too

Can't seal gapping holes made in lagging (3'-5') strand it goes in the oppisite direction then 5'-3'

RNA polymerase makes RNA primer to sart so DNA polymerase can continue

DNA ligase fills hole in DNA replication on lagging strand created when Okazaki fragments made

Helicase is the enzyme that unwinds or flattens out DNA helix

If DNA can't be unwound by helicase, topisomerase (also an enzyme) breaks DNA backbone so helicase can unwind it

Single strand binding proteins keep DNA from recoiling after helicase unwinds it

Leading stand is made continuously

Lagging strand is similar to road under construction (analogy)

RNA polymerase makes RNA primer so DNA polymerase has a starting point

Okazaki fragment is added onto primer

DNA has to get rid of primer (RNA)

Genome Project

http://en.wikipedia.org/wiki/Genome

This is a picture of multiple chromosome making up a genome. A genome is from an organism and its whole hereditary information encoded in DNA. DNA fingerprinting uses the genome of an organsim to identifiy individuals. It does not analyze the cells most imortant genes, which are almost identical in most people. DNA fingerprinting analyzes sections of DNA that have little or no known function bt var from one person to another. How it works.....A small sample of DNA is cut with a restrction enzyme. The fragments that are left are seperated by size using gel electrophoresis (The migration of electrically charged molecules through a fluid or gel under the influence of an electric field. Electrophoresis is used especially to separate combinations of compounds, such as fragments of DNA, for the purpose of studying their components). Fragments containing these variable regions are the detected with a DNA probe, revealing a series of DNA bands of various sizes. If enough combinations of restriction enzymes and probes are used, a pattern of bands is produced that can be distinguished from the pattern of any othr individual in the world. DNA samples can be taken from blood, sperm and hair follicles. With the Genome project Dr. Francis Collins and Dr Craig Venter attempted to sequence all human DNA. They were successful. The genome project is similar to what I've just explained about DNA fingerprinting. Scientisit use the autosomal chromosomes and the 2 sex chromosomes. They can locate genes in several ways. An open reading frome is a series of DNA bases that can produce part of a working mRNA sequence. The mRNA coding regions of most genes are interrupted by introns, but scienctists also have to find the special DNA sequences that mark the boundaries between intron and exonsin order to follow the gene through its complete length. When the process is complete the scietists can can pinpoint the gene's promotor and the start and stop sites for transcription. The Genome project continues today, as scientiss are still analyzing the huge amount of information in the DNA sequence looking for gene's that might provide clues to some of the basic properties of life. Also, Biotechnology companies are working on finding genetic information that could be useful in developing new drugs and treatments for diseases.

Conclusion:

Well, three of these chapters were a great explanation of how we were really built. We are all very unique individuals due to what we inherit. This can be good and bad because of the diseases carried in some genes. Scientists around the world have a never ending job because of DNA sequences. Obviously, science is limitless in its findings. You hear it every day about new discoveries or a cure for a certain disease. The chapter on cancer is a wake up call for people to take better care of themselves. Some diseases are preventable and others are inherited.

GENES AND INHERIDENCE

What is an inheritance? To most people it is money or property that is left to them by family

or close friends. There is a more important kind of inheritance and that is genes. Every living thing has a set of characteristics inherited from its parent or parents. Scientists have done

extraordinary work with finding out about the genes we inherit from our parents.

The work really begun in 1822 when Gregor Mendel did experiments with pea plants. He basically laid the foundation of the science of genetics. I would like to start with a few "key" definitions before I explain what Mendel did.

1. Genotype - genetic makeup of an organism

2. Phenotype - physical characteristics of an organism

3. Allele - one of a number of different forms of a gene

4. Cross-over - process in which homologous chromosomes exchange portions of their chromatids during meiosis

5. Dominant - the one pair of alternative alleles that masks the effects of the other when both are present in the same cell or organism

6. Recessive - an allele that produces it characteristics phenotype only when its allele is identical

Gregor Mendel conducted an experiment with pea plants. He worked at a monastery in a garden. Like many plants or flowers, the pea plants use parts of their flowers to reproduce. The male part of each flower produces pollen, which contain the male sex cells. The female part of the flower produces eggs-female sex cells. When pollen fertilized an egg cell, a seed for a new plant is formed. Pea plants normally reproduce by self pollination, in which pollen fertilizes the egg cells in the very same flower. When Mendel started his experiment he had several different stocks of pea plants. They self pollinated and would produce offspring identical to themselves. One of his seed stock produced tall plants and another short plants. One stock had green seeds and the other yellow seeds.

Peas are known to cross - pollinate. With cross pollination male sex cells in pollen from the flower of one plant fertilize from cross pollination have two plants as parents.

Mendel selected pea plants that he could mate with each other. What he did was, he cut away the male part of a flower. Then he dusted that flower with pollen from a second flower. The resulting seed were crosses between the two plants!!!! Also, when he crossed these he noticed that all the offspring were green. Remember, he used the sex cells from green and yellow seed plants. He called the offspring F1. Then he allowed all of the green F1 plants to self-pollinate. He referred to these offspring as the F2 generation. Mendel noticed a 3:1 ratio in pod color. About 3/4 of the F2 plants had green pods and about 1/4 had yellow pods. This whole process was termed Mendel's

Law of Segregation. This law states that allele pairs separate or segregate during gamete formation, and randomly unite at fertilization.
From Mendel's law of segregation we see that the alleles for a trait separate when gametes are formed (through a type of cell division called meiosis). These allele pairs are randomly united at fertilization. If a pair of alleles for a trait are the same they are called homozygous. If they are different they are called heterozygous. In meiosis each plant has to inherit a single copy of every gene from both parents. Since each pea plant has two parents each plant must carry two complete sets of genes. Then when an organism produces its own gametes those two sets of genes must be separated from each other so that each gamete contains just one set of genes. Also, when the chromosomes are homologous they are referred to as diploid, which means two sets Chromosomes from each parent. If there are a single set of chromosomes and a single set of genes these are referred to as haploid, which means "one set." Meiosis has several steps it goes through to produce daughter cells. It is the process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell. At the end of the steps meiosis produces four haploid daughter cells.

Genotype and phenotype play a key role. Genotype is the expression of genetic makeup and phenotype is the physical traits that you acquire. The genotype and phenotype are carried from generation to generation. The different forms of the genes are called alleles. This is where dominant and recessive come in. The dominance states that some alleles are dominant and others are recessive. An organism with a dominant allele for a particular form of a trait will always have that form. An organism with recessive allele for a particular form of a trait will have that form only when the dominant allele for the trait is not present. In Mendel's experiments,

the allele for tall plants was dominant and the allele for short plants was recessive. The allele for yellow seeds was dominant, while the allele for green seeds was recessive. To get a better understanding a Punnett Square, which was created by Reginald Punnett, the square that is for predicting the way alleles can combine. In this square the dominant and recessive are expressed with capital letters and lower case letters. If you see, for example TT, that would a dominant alleles and tt, would be recessive.

As part of this essay, we had to create a scenario of the Drosophilia fly ...........................
This picture shows the Punnett square and the offspring phenotype of the flies. Also, it show that the two fly's are heterogeneous. It also shows that one of the offspring inherited recessive genes.

Also, with this essay I did the dragon genetics lab. This was fun. It was like putting a puzzle together.
In this picture you can see that the dragons look identical. Also, you can see the chromosome X and the alleles that the dragon can inherited. It says at the bottom of the picture that I mastered the genotype to phenotype changes in the dragons. The genotype is the genetic makeup the dragon inherited and the phenotype is the physical traits, which you can see.

The research of genes and inheritance is very important. Scientists and researchers can predict what a child, for instance, may inherit. Some chromosomes fail to separate and the child my be born with downs syndrome. This particular disease is three copies of chromosome 21. We all inherit a set of chromosomes. Also, scientists can do a lot of testing on parents before they decide to get pregnant and see if a particular gene they have inherited could be expressed in the child's genes. Sometimes a particular disease may skip generation, but someone in that family is carrying "the gene" that will be expressed eventually. I should tell you that each cell in our bodies has 23 pairs of chromosome with a total of 46. There are 22 pairs of autosomes and one pair of sex chromosomes. The sex chromosomes are the X and Y and determine your gender.

I truly believe it is important for people to have genetic counseling before having a baby if they have certain family diseases that they are afraid of.

MODEL OF A HUMAN CELL

I made a model of a human cell with all of its internal parts. This was no easy task. The cell is highly organized. I used all sorts of interesting things around my house. I will list the parts and what their function is inside the cell…….

NUCLEUS – I used a fishing bobber, bright orange. The nucleus is in the center of a cell and houses the cell’s genetic material; DNA (deoxyribonucleic acid)

THE CELL - The whole cell is made of Styrofoam colored with crayon. We have millions of them in our bodies.

ROUGH ENDOPLASMIC RETICULUM – I used green yarn. Even though this particular organelle has tunnels, I think it is a good representation. The RER is studded with ribosomes’s given it is rough look. It is associated with the ribosome for protein synthesis.

LYSOSOME- I used a fuzzy yellow ball. These organelles are responsible for intercellular digestive system. They contain powerful hydrolytic enzymes which catalyze hydrolysis reaction. They take up the debris and foreign materials; like bacteria.

ENDOCYTOSIS VESICLE – I used a bottle cap with a marker. The endocytosis occurs when the plasma membrane dips outward and brings in a droplet of extracellular fluid. The lysosomes work very closely with these vesicles. Endo= within

PLASMA MEMBRANE – I used a large freezer bag. The plasma membrane surrounds and protects the cell. It is a protein studded lipid bilayer. It is separated from the extracellular fluid.

SMOOTH ENOPLASMIC RETICULUM – I used red paper. The SER does not contain ribosomes and that is why it is “smooth.” It serves as a central packaging and discharge site for molecules that are to be transported from the Endoplasmic Reticulum.

GOLGI COMPLEX (APPARATUS) – I used a pink pipe cleaner. The vesicles that bud off the Endoplasmic reticulum go to this organelle for processing the raw material into finished products. MITOCHONDRIA – I used green clay and magic marker. The magic marker was to draw the compartments within the mitochondria. It has 2 parts; the cristae, and the matrix. The mitochondria are the energy producing organelle they extract energy from the nutrients in food and transforms it into a usable form for cell activities. Generates ATP (adenosine diphosphate) with cellular respiration.
CILIA – I used green strands from a decorative straw I had. Cilia are the motile, hair like protrusions from the surface of the cell. The are responsible for sweeping away debris. Ie., in lungs it brings up sputum so we can spit it out.
RIBOSOMES – I used large black seeds. These are very important when it comes to protein synthesis because they are referred to as the “work benches.”
VAULT – I used a tip of a crayon. Serves as cellular trunks for transport from nucleus to cytoplasm.
PEROXISOME – I used a red berry (not real). They perform detoxification activities.
EXOCYTOTIC VESICLE – I used green clay with black seeds. These vesicles are opposite of the endocytotic vesicle in whereas they spill out of the cell.

CENTERIOLE – I used a bright orange crayon. They form the mitotic spindle during cell division.

Here is a picture of my completed cell model. I must say, at first I was stressed out about what to use, but I think it came together nicely. It is amazing how all the components or organelles inside the cell work together. The cell is the smallest unit that displays the properties of life.

Unfortunately, I did not get to include the inside of the nucleus, but I did take a picture of what I made. It is a piece of green Styrofoam with the middle cut out. I added water and lots of string to indicate the CHROMATIN; which are the strands of DNA when they are condensed and when they package themselves they are chromosomes.
supplies used for my mitosis or cell division model. Orange fuzzy ball for the nucleolus, straws , glue, large and small shells for the the cell and centromeres, the decorative things on the straws are used for the spindle fibers, paper plates and red and blue yarn for the chromosomes.
I also made a model of how mitosis works. Mitosis is cell division in which the chromosomes replicate before nuclear division, so that each of the two daughter cells receives a full set of chromosomes. There are four phases of mitosis. The picture of the chromatin shows the interphase of mitosis. The four stages are……. I also included the early prophase which is when the centrosomes have duplicated. Chromatin is condensing into chromosomes, and the nuclear envelop is fragmented.

Early Prophase- the picture shows in the shell the nucleolus disappeared, chromatin condensed.

1. PROPHASE – the chromatin condenses and becomes chromosomes. The condensed duplicate strand of DNA, or sister chromatids, remain joined together with the chromosome at the point call the centromere. Cells contain a pair the centromeres. The centromere forms the mitotic spindle during cell division. They divide and the daughter cells move to opposite ends of the cell.

In this picture I am showing the spindle fibers, and in the center of the yarn, the shells, are the centromeres.

2. METAPHASE- The nuclear membrane disappears. The 46 chromosomes each consisting of a pair of sister chromatin's align themselves at the equator of the cell. Each chromosome becomes attached to the spindle by several spindle fibers that extend from the centeriole to the centromere of the chromosomes.

In this picture you can see that for the Metahase all the chromosomes lined up at the equator.

3. ANAPHASE – The centromeres split converting each pair of sister chromatin's into two identical chromosomes, which separate and move towards opposite poles of the spindle. At the end of this phase, an identical set of 46 chromosomes is present in each of the poles, for a total of 92 chromosomes.

In this picture it shows the chromatin's part and become daughter cells.

4. TELOPHASE – The cytoplasm divides through formation and gradual tightening of the actin contractile ring at the midline of the cell. Form two separate daughter cell each with a full set of chromosomes. Spindles fibers disassemble, chromosomes uncoil to chromatin and the nuclear membrane reforms in each new cell.

Daughter cells are formed.

supplies used for DNA protein synthesis
I used clay for my tRNA, pipe cleaners for base pairing the helix of DNA and a poster board to put it on.

The pipe cleaners where not easy to put together, but I managed. In this photo you can see the DNA helix which is starting to unravel to make a mRNA. Also in this picture is the tRNA which translates amino acids to make proteins. I will go into further detail. First here is a better pic of my helix of DNA...................................................................................

In this picture I actually wrote that this is a DNA helix with base pairing. The different color pipe cleaners represent the bases These are the bases in DNA.........

C=Cytosine

G=Guanine

A=Adenine

T=Thymine

Transcription is what happens first. A strand of DNA is used as a template by the enzyme RNA polymerase to synthesis the mRNA (messenger RNA) which in turn leaves the nucleus and goes to the cytoplasm. The coding mRNA sequence can be described as a unit of 3 nucleotides called CODONS, which cause the insertion of a particular amino acid into a protein or termination of translation. Next is TRANSLATION. While the mRNA is in the cytoplasm the ribosomes, which contains the rRNA (ribosomal RNA) binds to it at the start codon, AUG, that is recognized only by the imitator tRNA (transferRNA). Amino acids are linked to the tRNA and bind to the appropriate codon in mRNA by forming complementary base pairing with the tRNA anticodon. In my picture of the model of tRNA and the ribosomes you can see that the ribosomes has two binding sites where codons bind to anticodons. The top of the ribosome is where codons bind to anticodons and the middle where the letters are is a tRNA amino acid is approaching.

The ribosome moves from codon to condon along the mRNA. Amino acids are added one by one translated into polypeptidic sequences dictated by DNA and represented by RNA. At the end a release factor binds to the stop codon terminating translation and releasing the complete polypeptide from the ribosome. RNA has one different base then DNA, which is urasil. Urasil replaces thymine.

I tried to make my explanation short and sweet by not going into much detail. Its hard to believe that all this is happening in our bodies while we are walking around, sleeping, or doing this report!!

MY COMPENDIUM - UNIT I THE CELL

MY COMPENDIUM
UNIT I - THE CELL

TABLE OF CONTENTS:
Characteristics of Life
Molecular levels, acids & bases
Water
Cells structure and function
Cell organelles and metabolism
Tissues, cellular junctions & Organ systems


CHARACTERISTICS OF LIFE

Life is an organized hierarchically and evolution is key. With evolution the first evidence was cellular life. It was a prokaryotic cell which scientists believed manifested into a eukaryotic cell. Humans have eukaryotic cells and bacteria have prokaryotic cells. All living things (organisms) share the characteristics of life. What I mean by that is we have the same internal functions in order to survive. Internally, we have a well organized system. The biological chart below shows the organization within us. Courteous of my professor Larry Frolich. Due to the pic being a little blurry I have explained what you are seeing on that chart. I will elaborate on some of these in my molecular levels section.

ATOMS – these are the smallest unit of an element composed of electron, protons and neutrons.

MOLECULES – is the union of two or more atoms.

CELL – the structural and functional unit of all living things.

TISSUE – a group of cells with a common structure and function

ORGAN – composed of tissues functioning together for a specific task

ORGAN SYSTEM – composed of several organs working together

ORGANISM – an individual, complex individuals contains organ systems

POPULATION – organisms of the same species in a particular area

COMMUNITY – interacting populations in a particular area

ECOSYSTEM – a community plus the physical environment

BIOSPHERE- regions of the earth’s crust, waters, and atmosphere inhabited by living organisms.

As you can see, it is not as complex as it seems. When you break down it makes sense. In order to survive and evolve there are six main components we all need :

ENERGY – eating food to survive. Food is broken down in the body and produces energy.
REPRODUCTION – creating a copy of yourself (offspring). This ensures extinction. This is done by genes which express a detailed copy of cells.
GROWTH & DEVELOPMENT – we grow and with that cells multiple. Development also includes repairs to cell if an injury occurs.
HOMEOSTATIC – is the internal environment of a living organism. All organ systems have a function in homeostasis EXAMPLE: digestive system; helps us absorb nutrients we need to survive.
STIMULI – EXAMPLE: hunger pains—“we eat” cold—“put a coat on,” Homeostasis would be impossible without stimuli. They work side by side as my example indicates
EVOLUTIONARY HISTORY – evolution is the process by which a species changes through time. Every organism is a new generation of OLD.

I would also like to point out that humans are related to animals. All organisms are placed in a classification which is called taxonomy. Carolus Linneus
Created these classifications. 1700's - Carols Linnaeus - Swedish Biologist Linnaeus Taxonomy"
· established a simple system for classifying and naming organisms
· Based on structural similarities of organism
· Binomial Nomenclature - 2 name naming system - still in use today.
· Created a system of groups called TAXA or TAXON
· Each Taxon is a category into which related organisms are placed
Approximately 2.5 million kinds of organisms identified

This is a sample of what the taxonomy looks like for humans…..

DOMAINS: Eurkarya
KINGDOM: Animalia
PHYLUM: Chordata (we have spinal cord)
CLASS: Mammalia
ORDER: Primates
FAMILY: Hominoidea (apes & humans), no tails
GENUS: Homo
SPECIES: Sapiens (homosapiens)

There are 2 other domains. Arachaea & Bacteria. Arachaea acts like bacteria. These are both prokaryotic and humans are eukaryotic.This just means that our cells are built differently. The prokaryotic are very small, no nuclei, no organelles and their cell wall is composed of
peptidoglycan, actually only bacteria has the peptidoglycan (made of peptide and glycogen- sugar). The eukaryotic cell is very well organized in that it has organelles hard at work inside, has a nuclei, plasma membrane, and are larger the prokaryotic.

MOLECULAR LEVEL

The molecular level is a lot of chemistry that is going on in our bodies, which people are unaware. Humans, along with other organisms, are an incredible piece of, well, machinery. We start out with atoms which I explained as being the smallest unit of an element composed of electrons that are negatively charged, protons that are positively charged and neutrons which have no charge, making them neutral. The electron, neutron, and protons are subunits of the atom. When the atom joins with others they become molecules of LIFE. Some atoms that join together are the same, but if they are different they are called a compound ie., hydrogen and oxygen = water. There are 2 bonds that hold atoms together.

COVALENT BOND – this is sharing of electrons. It is a very strong bond.
IONIC BOND – is a chemical bond when ions are attracted to one another by opposite charges. Ie., cation – positive ion and anion
Negatively charged ion

A great example of an ionic bond is table salt. When salt is placed in water, what does it do? It dissolves. That’s where the cation ion
and anion ion come together. There is also hydrogen bonds. These bonds are extremely weak and are easily broken. A great example
of this is H & O2= WATER. There are 4 very important molecules in life.

PROTEINS – plays a crucial role in all biological processes. Main structural components of a cell. All chemical reactions in the body are catalyzed by enzymes all of which are proteins. They are made up of a monomer call amino acids. Structure of protein organization. They actually fold by steps. First are the primary structure, secondary structure, tertiary structure and lastly quaternary structure. All made of polypeptide chains.
CARBOHYDRATES – 3 types; monosaccharide which are simple sugars mono= one. Disaccharides (di=2) which are sugars formed by linking 2 monosaccharide molecules together through a covalent bond ie., table sugar, lactose. Polysaccharides (poly=many) carbohydrate molecules bond together and form a long chain that contains many saccharides units ie., glycogen, starch, cellulose.
FATS OR LIPIDS – these are insoluble in water. There are 2 components of lipids. Fatty acids and alcohol.
NUCLEIC ACIDS- Two types; DNA and RNA. Are responsible for storing and using genetic information in living cells and passing it on to future generations. DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) contains organic nitrogenous base, a sugar, and a phosphate group.

ACIDS & BASES

Acids and bases refer to a pH scale. Acids, which you probably know are in a lot of stuff we consume like, tomatoes, juices, and sauces.
Bases are also in a lot stuff we consume like; egg whites, milk, and even human blood (hope no one consumes that)! Substances like hydrochloric acid donate hydrogen ions to a solution making it acidic. Substances with sodium hydroxide accept hydrogen ions or contain hydroxyl ions and are very basic or alkaline. Scientists use the pH scale which ranges from 0 – 14 to indicate acid or alkaline. Acid is 0 – 6 and alkaline is 7.5 to 14. With pure water the number of hydrogen ions is the same as the of hydroxyl ions so water has a pH of 7 and is neutral. Ahhhhh, WATER, which bring me to my next topic.

WATER

Water is the universal solvent!! Water molecules are cohesive because of their polarity and hydrogen bonds. Water is also the most abundant molecule in living organisms. As I said above, water is connected by hydrogen bonds. The electrons (negative charge) are closer to the oxygen
atom, the oxygen atom becomes slightly negative and the hydrogen are slightly positive. This makes water a polar molecule. Water plays such a key role in our body. One of it great roles is the way it interacts with the human cell. The cell being selectively permeable lets water easily permeate the membrane. There are different ways water can get through. One is diffusion, in which it involves the movement of ions or molecules from high concentration to low concentration until the sides are equal. Secondly is osmosis which involves the flow of water across the cell membrane. These two are pretty much identical. The concentration gradient exists when the amount of a solute found in one region is greater then the amount of the solute in another. Things that influence the rate of diffusion/osmosis is the particle size, temperature of the system, solvent density. The stepper the concentration gradient and smaller the particle size the faster the rate of diffusion. The cell membrane is a great example when it comes to the next 3 terms because of the intercellular fluid is within the cell and the ECF =extracellular fluid is outside the cell. When the ECF has a lower osmotic pressure then the ICF the extracelluar fluid is said to be HYPOTONIC and water will flow into the cell causing the cell to swell and
possibly burst. When the cell has low osmotic pressure, water flows out of the cell and the cell will shrivel up making it HYPERTONIC. If the fluids have identical osmotic pressure it is said to be ISOTONIC. There are also to important processes that occur with water. Hydrolysis which is splitting of a compound by the addition of water. Dehydration is another process that occurs and it results from a covalent bond with the accompanying loss of a water molecule.

CELL STRUCTURE AND FUNCTION

The cell functions in many different ways for our survival. I have composed a list of these functions.

obtains food (nutrients) and oxygen from the environment surrounding the cell
performs chemical reactions that use the nutrients and oxygen to provide energy for the cell. Ie., food + O2 + H2O + energy
eliminating CO2 and other wastes produced during the chemical reactions
synthesizes proteins and other components needed for cell structure, growth and carrying out a cell function
controlling the exchange of materials between the cell and its surrounding environment
moving material from one part of the cell to another in carrying out cell activities, some move entirely.
being sensitive and responsive to change in surrounding environment
reproducing

The cells structure is much more complicated. It has several organelles that function together. This is a list of the structures of the cell and a brief description of how they function.

CELL MEMBRANE – consists of mostly lipids, fats, and proteins. This membrane is selectively permeable, meaning some particles are easily let in and others require energy to pass through. Keeps Intracellular fluid within the cells form mingling with Extracellular fluid outside of the cells. Encloses each cell.
PHOSPHLIPIDS - have a polar (charged) head containing a negatively charged phosphate group and 2 nonpolar (electrically neutral) fatty acid tails. Structure of this is critical of membrane amipathic nature, meaning it contains both polar and nonpolar domains. The polar ends are Hydrophilic because it can interact with water molecules, which are also polar. The nonpolar end is Hydrophobic and will not mix with water. The 2 sided molecule self assemble into a lipid bilayer!
NUCLEUS – the largest single organized cell component. Houses the cells genetic material DNA (deoxyribonucleic acid) directs protein synthesis, serves as a genetic blueprint during cell replication.
CYTOPLASM – is the portion of the cell interior not occupied by the nucleus. Contains organelles (little organs) dispersed with the cytosol
ORGANELLES – each organelle is a separate compartment within the cell that is enclosed by a membrane similar to the plasma membrane. They are like intercellular specialty shops, each carrying out specific set of chemicals for carrying out particular cell function.
CYTOSOL - is the extension of the cytoplasm. Has an elaborate protein network called a cytoskeleton. The cytoskeleton gives the cell shape, provides internal organization and regulates movement. It contains three elements; microtubules, (movement of cell components), microfilaments; (movement of the cell or changes in cell shape) and intermediate filaments; (strictly structural, uses keratin).
CILIA AND FLAGELLA – these produce movement. Cilia is (in the respiratory tract, moves an egg along the oviduct) sweep unwanted particles trapped in mucous back up the throat, which helps clean out the lungs. Flagella are a whip-like movement with long tails a good example of flagella is male sperm. The flagella is the tail and help the sperm swim. Both of these are grown from basal bodies.

LIST OF ORGANELLES AND BRIEF FUNCTION

RIBOSOMES – carries out protein synthesis.
ENDOPLASMIC RETICULUM – primarily a protein and lipid manufacturing factory
SMOOTH ER – lipid and steroid metabolism. Portions of the smooth ER “bud off” after receiving synthesized proteins and lipids the pinched off forming transport vesicles. Meshwork of tiny interconnected tubules.
ROUGH ER - ribosome’s attached rRNA (ribosomal RNA) flattened sacs is part of protein synthesis making vesicles
GOLGI COMPLEX - stacked flattened membrane enclosed sacs. Processes raw material into finished products, pinched into vesicles with final product – docking markers. Each vesicle can doc and unload only at the appropriate docking marker acceptor.
LYOSOMES – performed in the golgi complex. Contains hydrolytic enzymes which catalyze (break down) hydrolysis reactions. Uses endocytosis (released particles within the cell). There are three types of endocytosis. Pinocytosis (cell drinking) brings in a droplet of ECF. Receptor-mediated endocytosis; highly selective process that enables cells to import specific large molecules. (traps proteins inside the cell, ie., cholesterol. Phagocytosis (cell eating) engulfs large substances, forming an intercellular vacuole.
MITOCHONDRIA - energy producing organelle. They extract energy from the nutrients in food and transform it into a useable form for cell activities. Most importantly, generates ATP (adenosine triphosphate- our energy). Has 2 parts cristae – inner membrane that forms series of shelves. Also increases the surface area for electron transport chain (which occurs in metabolism and the matrix which consists of hundreds of different dissolved enzymes.
I would like to explain how the process of cellular respiration works. Metabolism is the total chemical reactions that occur in a cell. It starts with glycolysis, (happens in the cytoplasm) which is the break down of glucose and turns into pyruvate acid or it can produce fermentation in which lactate is produced Lactate is what makes that burning sensation when you are working out. You feel a burn. This step does not require oxygen, making it anaerobic. Next step is the Krebs cycle (happens in the matrix of the mitochondria), which requires oxygen (aerobic), and produces ATP at the end of its cycle, 2 to be exact. Third step is the Electron transport chain, (happen in the cristae of the mitochondria) which also requires oxygen and produces the most ATP= 32. These steps are highly organized. They use electrons, coenzymes NAD, (nictinamide adenine dinucleotide), release of carbon dioxide. These steps are really hard to put into works, but I understand completely how they work. I could go on forever. There would be not end to this compendium.

HOW PARTICLES OR PROTEINS PASS THROUGH THE PLASMA MEMBRANE

I explained early how diffusion and osmosis worked, but in order for proteins to pass over there is a special transport because they are so large.
Active transport the moves from low concentration to high concentration, which is opposite of osmosis. Active transport requires a protein carrier and use of cellular energy obtained from the breakdown of ATP. Facilitated diffusion does not require ATP it uses a carrier to transport downhill.
The sodium/potassium pump is active transport pump critically important in the ability of nerve and muscle cells to generate electrical signals essential to their functioning. 3 Na+ (sodium) out of the cell, 2 K (potassium) pumped into the cell.


TISSUES, CELLULAR JUNCTIONS & ORGAN SYSTEMS

There are four main tissue types. Tissues are composed of specialized cells of the same type to perform a common function in the body.

MUSCLE TISSUE - consists of cells specialized for contracting and generating force. Three types. Skeletal muscle; moves skeleton. Cardiac muscle; pumps blood. Smooth muscle; encloses and controls movement of contents through hollow tubes and organs.
NERVOUS TISSUE – consists of cells (neurons) specialized for initiating and transmitting electrical impulses. These are found in the brain, spinal cord, and external environment.
EPITHELIAL TISSUE - cells specialized for exchanging material between the cell and its environment. Any substance that crosses the body proper must cross an epithelial barrier. Our bodies’ organs are covered with epithelial tissue. It is organized into 2 type’s f structures. Epithelial sheets; serves as boundary, ie., GI tract, lungs. Secretory glands; exocrine gland; secretes through ducts to outside of the body or into a cavity that opens to the outside. Endocrine gland; lacks ducts and release their secretory products known as hormones in the blood stream, ie pancreas secretes insulin. There are also 3 types of epithelial tissues. Squamous epithelium its shape and arrangement helps permit exchanges of substances, ie air sac of lungs and walls of blood vessels. Cuboidal epithelium, single layer. Found in glands and contain microvilli that help increase the surface area for absorption. Columnar epithelium, lines the widepipe, also, they have cilia which help trap mucous and send it back to the throat to get rid of the debris.
CONNECTIVE TISSUE – connects, supports, and anchors. Includes diverse structures as the loose connective tissue attaches epithelial tissues to underlying structures; tendons. Except for blood, the cells within connective tissue produce specific structural molecules that release into the extracellular spaces between cells. One molecule is the rubber band like protein called ELASTIN- this facilitates the stretching and recoiling of structures such as lungs.

CELLUALR JUNCTIONS


These junctions help tissue perform its particular function. There are 3 types

DESMOSOMES – (cells being pushed together) “spot rivets” that anchor together to closely adjacent but nontouching cells. Found in tissues; skin, heart and uterus. There are 2 components. A pair of dense, button like cytoplasmic thickening known as plaque and strong filaments that extends across the space between the 2 cells and attach to the plaque on both sides
TIGHT JUNCTIONS- adjacent cells firmly bind with each other to seal off passageways between 2 cells
GAP JUNCTIONS – (communicating junctions) As the name implies a gap exists between adjacent cells which are linked by small connecting tunnels formed by connexons. They are made up of 6 protein subunits. Most abundant in cardiac muscle.

ORGAN SYSTEMS

All these system work together to promote homeostasis!! Negative feedback is a one of the primary homeostatic mechanism that keeps a variable, like blood glucose level close to a set point. Example…when body temp rises the response is to seat, evaporating cooling. Vasodilatation vessels on the surface of the skin increase in diameter – dissipates heat; increases fluid, thirst, less urination – remove clothing
Positive feedback – works against homeostasis. There is no set point and the body is not regulated. It is useful in the birthing process as the cervix dilates it produces oxitocin and with further dilation the cervix producing more oxitocin.
There are 11 organ systems. Here is a pic for you to view. I will give a brief description of each.

NERVOUS SYSTEM - Acts through electrical signals to control rapid responses of the body.
CARDIOVASCULAR SYSTEM – Transports oxygen and nutrients to tissue cell and transports wastes away from cells.
DIGESTIVE SYSTEM – Obtains nutrients, water, and electrolytes from the external environment and transfers them into the plasma and eliminates undigested food residue to the external environment.
MUSCULAR/SKELETAL SYSTEM – Supports and protects body parts and allow body movement Heat-generating muscle contractions are important in temperature regulation.
INTEGUMENTARY SYSTEM – Serves as a protective barrier the external environment and the remainder of the body; the sweat glands and adjustments in skin blood flow are important in temperature regulation
IMMUNE SYSTEM – Defends against foreign invaders and cancer cells; pave the way for tissue repair
RESPIRATORY SYSTEM – Obtains oxygen from and eliminates carbon dioxide to the external environment, helps regulate pH by adjusting the rate of removal of acid-forming carbon dioxide.
URINARY SYSTEM – Important in regulating the volume, electrolytes composition, and pH of the internal environment. Removes wastes and excess water, salt, acid, and other electrolytes form the plasma and eliminates then in the urine.
REPORDUCTIVE SYSTEM – This doesn’t really help with homeostasis, but is important for perpetuation of out species.
ENDOCRINE SYSTEM – Acts by means of hormones secreted into the blood stream to regulate processes that require duration rather then speed i.e., metabolic activities, water and electrolyte balance.
LYMPHATIC SYSTEM – Helps maintain blood volume by collecting excess tissue fluid and returning it via lymphatic vessels to the cardiovascular veins. Defends against disease.

Conclusion: I am sure that I may not have touched on some points, but isn’t that what a compendium is. I tried to condense a lot of information into
my compendium that I thought was important. The body is a complex system, but once you understand it; it is AMAZING!!!! I tried to include pictures from the world wide web as best I could. I feel that pictures help visualize what is being explained. These are the wesites where I

copied some pictures.......

www.fotosearch.com/photos-images/atoms.html

http://www.wikipedia.com/

www.biologie.uni-hamburg.de/b-online/e22/22.htm